Automatic train stop system



G. C. WHITNEY AUTOMATIC TRAIN STOP SYSTEM April 27, 1937.

Filed July 6, 1935 2 Sheets-Sheet 1 C/osed arr/y in l SEE NoreoN 56.4.

April 27, 1937. G. c. WHITNEY AUTOMATIC TRAIN STOP SYSTEM 2 Sheets-Sheet 2 Filed July 6, 1933 mnu? um.. no Q /A/l/E/v TDR m UWM.

.0 um@ EUWW Patented Apr. 27, 1937 UNITED STATES NTA OFFICE 11 Claims.

This invention relates in general to automatic train stop systems and automatic block signal systems for railroads and more particularly, though not exclusively, to novel means for controlling the automatic train stop associated with an automatic block signal when said block signal is displaying a restrictive indication and is applicable Whether the block signal system is operated or controlled electrically or electro-pneumatically and whether the train stop system is operated or controlled electrically or electropneumatically and is also applicable whether coaction between the train stop system and a train is carried into eiect mechanically or electrically.

The established practice in the art of railway signalling and train control for rapid transit railroads in particular is to provide an automatic block signal system adapted to convey information, in the form of colored light, to the opera,- tor of an approaching train, as to the occupancy or non-occupancy of the track in the advance territory. Associated with each block signal there is provided an automatic train stop mechanism to stop the passage of a train, by causing application of the train brakes, in the event that a train attempts to pass a signal when such signal is displaying a stop indication. Both the signal and train stop mechanism are controlled by track circuits. In all of these systems the train stop mechanism assumes the non-stopping position when the signal indicates caution or proceed. In one of these systems the train stop mechanism assumes the stopping position immediately after the train passes it. In another ofvthese systems the train stop mechanism remains in the non-stopping position until the rear end of the train has passed an appreciable distance by it and this even though the signal may be indicating stop. In both of these systems means are provided to enable the train operator to put the train stop mechanism in a nonstopping position when the signal indicates stopin the rst mentioned system the means includes a key to be actuated by the train operator and in the second mentioned system the effect is produced by arranging the track circuit, the signal, and the train stop mechanism in a definite order. Both of these systems may be arranged further to prevent the signal from displaying a caution or proceed indication unless and until after the associated train stop has assumed the stopping position after the passing of a train. The object sought is to prevent rear end collisions. This object is attained only in the rst men- 5 tioned system and at the cost of the time neces- CII sary to operate the key and this means loss of track capacity. In the second mentioned system the object sought is attained only in part because `of the delay in the train stop mechanism assuming the stopping position and this means reduced protection to trains. Furthermore, the required denite order of arrangement in the second mentioned system leads to high installation costs because subway and elevated structures must be modied and expensive additional equipment must be installed to obtain curve protection. And, again, the deiinite order of arrangement required by the second mentioned system, at times, prevents the normal functioning of the signaling system and thereby causes loss in track capacity'.

The objects of my invention, as hereinafter disclosed, are (l) to provide a system in which the automatic train stop mechanism assumes the stopping position immediately after the rear end of the train has passed it; (2) to provide a system permitting train operation of the train stop mechanism and thereby avoid need for key operation; (3) to provide a system to insure that a train stop mechanism in the rear of the train is in the stopping position to protect said train when a train stop mechanism is to be put in the non-stopping position by a train; (4) to carry the objects of this invention into execution with a minimum of definite order of arrangement and apparatus and therefore at a minimum cost; and (5) to avoid interference with the regular operation of the block signal system.

In describing this invention in detail, reference will be made to the accompanying drawings consisting of Figs. 1 to 4; showing diagrammatically the broad novelty of this invention in its simple fundamental form in Fig. l in a manner to make it easy to understand the invention rather than with the idea of showing any preferred ernbodiment and in Figs. 2 and 3 are shown variations in detail in carrying the invention into practice and in Fig. 4 I have shown an automatic block signal system combined with this invention. Similar reference characters are used to represent similar parts in all of the figures.

Referring now to Fig. 1; there is shown a stretch of railroad track including track rails 5 and Si electrically separated into track sections A, B, and C by insulated track rail joints 'l' to permit the working of a track circuit in the usual manner. The track rails of each section A, B, and C are included as a part of the well-known normally closed track circuit-sec. C having a source of energy 8 and a track relay 9 (referred to in the claims and elsewhere in the specification as the second track circuit)-sec. B having a source of energy and track relay I@ (referred to in the claims and elsewhere in the specifica-- tion as the first track circuit)-sec. A is similarly equipped but not illustrated because it is not necessary to a clear understanding of this invention. The functioning of these track circuits is well understood in the art and need not be described other than to state that, in regular track circuit operation, certain contacts 0perated by the track relay are closed only when the track section is not occupied by a train and these contacts are termed front contacts and certain contacts operated by the track relay are closed only when the track section is Yoccupied by a train and these contacts are termed back contacts. l

For each track section I provide an automatic train stop mechanism situated at a selected point along the wayside and arranged to co-act, mechanically, electrically, or otherwise as the case may be, with train carried apparatus to cause application of the train brakes when said wayside train stop mechanism is in the stopping position and a train attempts to pass it but which train stop mechanism will not cause application of the train brakes when said train stop mechanism is in the non-stopping position. The point selected for the location of these wayside train stop mechanisms II (for sec. C) and I2 (for sec. B) is located at a distance. X from the beginning of the respective track section to allow time for a slow operating train stop mechanism to assume the nonstopping position and thereby control the speed of a train at this point by requiring the lapse of a predetermined time interval while the front end of the train is passing over said distance X.

Distance X will not be longer than the distance between the front co-acting train carried apparatus and the rear wheels of the shortest train operated.

The operating mechanism I3 for train stop II cannot operate instantly in operating train stop I I from the stopping position to the non-stopping position and this inherent time for operation is taken into consideration in determining distance X. This inherent time for operation is substantially constant for mechanisms of the same kind but different as between different kinds. 'Ihese train stop mechanisms are arranged, by means 0f counterweights, compression springs, or the like, for the mechanical type, to assume the stopping position where the train stop arm II will .co-act with train carried apparatus to cause application of the train brakes in the event that a train attempts to pass when train stop II is in the stopping position. The train stop and operating mechanisms always assume said stopping position when they are not controlled to the nonstopping position.

As illustrated in the drawings all wayside train stops are located on the same side of the track but it is to be understood that said wayside train stops may be located on either or both sides of the track and arranged to co-act, when in the stopping position, with the train carried apparatus.

The co-acting train carried apparatus may be located on either or both sides of the train, in front of the train truck or in the rear of the train truck, and at the front end of the train or at the rear end'of the train, as desired.

Solely in the interest of simplicity the source of energy for other than the track circuits is not shown in the figures, but it is to be understood that a suitable source or sources of energy is provided and represented by the characters B and O for the terminals of such a source of energy and which may be direct or alternating current.

Train stop operating mechanism I3 for train stop II is controlled by a. circuit which may be traced as follows: from B to contact I4, closed only when train stop I2 is in the stopping position, wire I5, track relay contact I6 closed only when sec. B is occupied by a train, wire Il, track relay contact I8 closed only when sec. C is occupied by a train, wire I9, to operating mechanism I3 to O. When this circuit is complete, that is, all contacts are closed, operating mechanism I3 will be energized and train stop II will assume the non-stopping position. When this circuit is not complete, due to any of the contacts being open, train stop II will be in the stopping position. Fig. 1 shows train stops II and i2 in the stopping position. The train stop operating mechanism for train stop I2 is similarly controlled.

Distance Y is determined solely by the condition that contact I4 on train stop I2, closed only in the stopping position of I2, is used in the control circuit of train stop operating mechanism I3 for train stop Ii. Therefore distance Y will be such as to permit of train stop I 2 being in the stopping position before the front end of a train enters sec. C. When the approach block (sec. B) is shorter than the longest train operated on the railroad contact I4 is located on a train stop farther in the rear.

In order that the train operator may know the location and position of train stop II I provide Visual indication in the form of two distinctly differently colored lamps at each train stop. One of these lamps, preferably red in color, is controlled by a circuit which may be traced as follows: from B to contact 20, closed only when train stop II is in the stopping position, wire 2l, lamp 22, to O. The other of these lamps, preferably of color White, yellow, or green, is controlled by a circuit which may be traced as follows: from B to contact 23, closed only when train stop iI is in the non-stopping position, wire 2&3, lamp 25, to O.

In proceeding over the track in the direction of the arrow the front end of the train enters sec. B and continues on to enter sec. C. When the train enters sec. B, contact I5 closes and when the front end of said train enters sec. C, contact i8 closes. When the rear end of said train passes out of sec. A, (before the front end reaches sec. C) train stop I2 assumes the stopping position to stop a following train. The control circuit for operating mechanism I3 is now complete. Train stop II assumes the non-stopping position and the associated lamp indication changes accordingly to inform the train operator. When the rear end of said train passes out of sec. B, contact I5 on track relay IE! opens the control circuit for I3; train stop II assumes the stopping position; and the visual lamp indication changes accordingly.

As pointed out hereinbefore distance X is determined by the inherent time required for operation of the train stop operating mechanism Izl and this time interval is taken into consideration in enforcing a predetermined train speed. For example, if mechanism I3 requires 2 seconds for operation and the selected train speed to be enforced is 5 miles per hour, then distance X amazed will bc l5 feet, because a train speed of;5rmiles. per hcuris equal, anpreximatcly, to `'1.5: feetper second Again, if the inherent` time for saidl Operation is 2 seconds: and` the allowable train` speed islO miles per hour, then distance X will be 3Q feet, and so` on. But, if the inherent `oper-` ation time ofA I3; is .5 secondandA the allowable train speed is 5` miles per hour, then distance X will be 3.75 feet. is not practicable to operate a train with distance X as short as 3,75 feet. I provide for this condition by including a time delaydevice, fixed or, adjustable as desired, in the control circuit ci'v the train stop operating mechanism I3.`

With the inclusion of a time delay meansa definite distance X is noA longer` necessary and any distance X suited to practical railroad construction and operation may be, used and the train speed will be restricted by the time delayv factor as will be explained hereinafter;V

Referring now toFig.` 2 Fig. 2,y is` similar tc Fig. 1 in all respects except that a timedelayfde.-

vice 26 has been included in the control ci-rcuit of mechanism I3to lengthen the time of i operan tion and Contact I4, of Fig. 1 is not included. Time delay device 2li` isl of thefslow pick up type of relay4 with :fixed` oradjustable time factor as desired. This type of relay does. not close its front contact 2l to wire 28, until after theA lapse of the established interval of time after said relay 26zhas been energized and which` opens contact 35 (Fig. 3) from Wire 36 4practically simul-` taneously With the closing of'v contact 2.1 to wire 28, and Which openssaid contact 2I from wire 28` and closes said contact 35 to Wire 3.6' linmediately when said relay 26 is deenergized. Device` 26` is controlled by aV circuit which may be traced asY follows: from Btc track relay contact I6, Wire I'I, track relay contact I 8, wire I9, to device 26, to O. Mechanism I3..is controlled by a circuit Iwhich may be traced as follows: from B to contact 21, closed only after the lapse of the established time interval after the control circuit for device 26, has been completedwire f 28, to operatingmechanism I3. to` O.

Referring to Fig. 2 ;-.-.the. operation is as` follows:- In proceeding over the track in the direction of the arrow the4 front endof the. train enters sec. B and continues on to enter sec. C. When the. train enters sec. B, contact I6; closes and when the front end of said train enters sec. C, contact I8 closes. The control circuit for 26 is now complete. lished time interval contact 21 closes. `The control circuit formechanism I3 is now complete. Therefore, train stop II assumes the non-stopping position and the visual indication changes accordingly to inform` the train operator. When theirear end of said train passes'outl of sec. B, contact I6V opens to open the control circuit of device 26; When the control circuit of 26opens, contact 2I opens immediately. The control circuit of I3 is now open. Therefore, train stop II assumes the stopping position with appropriate change in theJ visual indication as before. Fig. 2 shows train stop I I in the stopping position.

In Figs. 1 and 2,` the system illustrated and described may be termed "normal danger from the fact that the automatic train stop is always in the stopping position except when it assumes the non-stopping position to permit the passing of a train at a` predetermined speed. When there is no train in the advance.f territory it is desirable that the` train proceed at a' higher speed, and this requires that means betprovidedv In actual railroad operation it` After the` lapse of `the estab- Sc that the train Stop. may. assume the non-` stcpping position Whenever the territory ad'. Vance of the train stop II is not occupied by a t;1alr1r but. Whichwill retain the advantages hereinlcefore explained in connection with Fig. 2.

In Flic;` 3 such` a system,` known asl normal clear is illustrated and the system of Fig. 2 is incorporated therein.

Referring nowto Fig; 3,; there is shown a stretch of track ,divided into track, sections A, Bc and C, andan additional track section D has been shown., Sec. D is provided with source of energy 8; and; track relay 29 and is referred to the claimsl andelsewhere in the specification as the third track circuit. 'Ifhenorinal clearing circuitl for-train stop Ii'maybe tracedas follows; from B to. front Contact 3| on track relay 2,9; to wire 32;, to front contact 33ori track relay` 9, to wire` 34, to wire 30, to operating mechanism I3, to O. There is also` provided aV normal re-` tainingl circuit lfor trainA stop I I and this` circuit may Ice traced, as follows;` from B to contact I6 on track relay I0, to wire aI'I, to wire I'I, to back Contact 351011 device 26, to Wire 36, to back contact `3 .'I on track relay 9, to Wire 38, to contact 39qonoperating mechanism I3 and closed only when trainl stop II is in the non-stopping position, to wire 3I'I,` to operating mechanism I3, to O. The normal clearing circuit for train stop I2 may be 4traced asiollows: from B to front contact 4I)` on track relay 9, to Wire 36, to back contact 35,011 device 2,6to wire I'I, to front contact 5I on track relay. I0, to Wire II2, to wire 43, to operating mecl'ianism` I3aifor train stop I2, to, O. It`

will be observed that the normal` clearing circuit for train stop operating mechanism I3a for train stop IZ, in part also serves for the normal retaining, circuit for train stop operating mechanism I3: for train stop II, When either the normal clearing circuit or the normal retainingl circuitis complete the respective train stop will assume or be retained in the non-stopping position, Except for the inclusion, ofcontact 35 in the circuit which serves in part as the normal clearing circuit for mechanism I3a, hereinbefore traced,` and which serves` in partas the normal retaining circuit for mechanism I3, hereinbefore traced, for checking purpose and to permit the incorporation of my invention, this normal clearing circuit and normal retaining circuit is old andwell understood in the art.

My invention as incorporated in Fig. 3 is the same as shown and described in connection` with Fig, 2. Because of the fact that the character reference for the control circuit of device 25 is differentsaid `circuit is tracedin Fig; 31 as follower;

from. B` to Contact I6 closed only when sec. B is occupied by a train, to` Wire all, to` Wire -I I.; tof-Wire;

IIa, to contact I8 closed onlywhen sec. C is occupied by a train, to Wire` IS, to device 2'6, to O. The` circuit for the control of mechanism I3 via devicev26, is traced asfollows: from B to contact 21 closed only after the lapse of the established interval of time after thercontrol circuit for deviceV 26;,has been completed, Wire 28, to wire 30, to mechanism I3, to O. As explained hereinbefore contact 21 does not close until the lapse of the established time interval after the control circuit for ldevice 26 is complete and that contact 21 opensimmediately` when the control circuit for 26u opens. As hereinbefore pointed out,` contact 35 controlled by device 2liy remains closed until the lapse of said established time interval after the control circuit for device 25 `is complete, and contact 35: closes immediately When the control I train stop II.

' the visual indication.

circuit for 26 opens. In Fig. 3 the visual indication scheme is the same as in Figs. 1 and 2 and in connection therewith it should be noted that the circuit including contact 23 is complete indicating that train stop I I is in the non-stopping position. Fig. 3 shows train stops I I and I2 in the non-stopping position.

The circuit and contacts which control time delay means device 2'6, hereinbefore described, and the control of mechanism I3 by said time delay means, device 26, hereinbefore described, provide an auxiliary means for operating train stop II from the stopping position to the non-stopping position and is referred to as auxiliary means hereinafter and in the claims.

The purpose of incorporating my invention in a normal clear train stop system, as in Fig. 3, is to provide a means whereby a following train may pass, at restricted speed, train stop II before the rear end of a leading train has passed out of sec. D. The operation is explained hereinafter.

Referring to Fig. 3; as shown, the track, consisting of secs. A, B, C, and D, is not occupied, the track relay front contacts are closed, train stop I i is in the non-stopping position, and the visual indication, to inform a train operator, in sec. B, that he may proceed at speed, is displayed at In proceeding over the track in the direction of the arrow the train enters sec. B and continues on to enter secs. C and D. The normal clearing circuit for mechanism I3, hereinbefore described, remains complete until the train enters sec. C. The normal retaining circuit for mechaniSm I3, hereinbefore traced, is completed at the time the train enters sec. C, by the closing of contact I6 on track relay IU (closed when the train entered sec. B) and contact 31 on track relay 9 closed when the train entered sec. C. Therefore, while the train is occupying secs. B and C, train stop I I lis retained in the non-stopping position. When the rear end of said train passes out of sec. B, the normal retaining circuit is opened at contact I6 and train stop I I assumes the stopping position with appropriate change in Train stop I I now remains in the stopping position until the rear end of said train passes out of sec. D (at which time the normal clearing circuit is reestablished) unless said train stop I I be put in the non-stopping position by a following train in a manner now to be described, Assume that the first train stopped with its rear end occupying sec. D. Train stop II is in the stopping position because the normal clearing circuit is open at contact 3l and the normal retaining circuit is open at contacts I6, 3l, and 39. A following train enters sec. B and continues on to enter sec. C. At the time said following train enters sec. B, contact I6 on track relay I0 closes and at the time said following train enters sec. C, contact I8 on track relay 9 closesI and thus the circuit for the control of time delay device 26 from B, contact I6, wire all, wire I'Ia, contact I8, wire I9, to device 2'6, to O, is completed. After the lapse of the established time interval of device 26, contact 2'! on device 26 closes to complete a circuit from B, to contact 21 (now closed), to wire 28, to wire 30, to mechanism I3, to O, whereupon train stop I I is operated to the non-stopping position and said following train may pass. The purpose of time delay device 26 and control circuit therefor and the control of train stop II by said device 26 is to provide a means whereby train stop I I may be operated to the non-stopping position independently of the normal clearing circuit. In view of the fact that the established time interval for device 26 does not start until after contact I8 closes (due to said following train entering sec. C) and that contact 2l does not close, to complete the circuit to mechanism I3, until at the end of said time interval, it is evident that said train stop I I will remain in the stopping position until after the established time interval after said following train enters sec. C (closing of contact I8). The control of mechanism I3 by time delay device 26, therefore, provides means whereby the speed of a moving train is restricted to a predetermined speed while passing over distance X, while the normal clearing circuit of mechanism I 3 is not complete. It is manifest that the brakes of said following train will be applied by train stop I I in the event that the established time interval for device 26 has not elapsed before said train reaches said train stop II. When the rear end of said following train passes out of sec. B train stop II assumes the stopping position, and so on. As explained hereinbefore, mechanism I3 does not operate instantaneously; therefore, the opening of contact 35 in the normal retaining circuit is followed sufficiently soon by the closing of contact 2l to prevent train stop I I assuming the stopping position under these circumstances.

The economic operation of a railroad requires that trains be operated at varying speeds according as more or less of the track in the advance territory is or is not occupied by a train and the means used to inform the train operator consists of a block signal system controlled automatically by track circuits. Such a system incorporating my invention is shown in Fig. 4.

Referring to- Fig. 4; there is shown a stretch of track divided into track sections A, B, C, D, and E, which are equipped with track circuits in the usual manner as hereinbefore explained. At the entrance to each track section there is shown a block signal suitably equipped with R (red), Y (yellow), and G (green) lamps and arranged to inform the train operator whether the train should stop', proceed with caution, or proceed at speed, respectively. In general the lighting of these signal lamps is selectively controlled so that only one lamp at a block signal is lighted at any given time and this condition is obtained by means of a system of circuits controlled by track circuits and in turn controlling the lamp circuits.

The means involved to obtain the selective cony trol of the R, Y, and G lamps includes an H relay and control circuit therefor and a D relay and control circuit therefor. The circuit for the H relay for the signal at the entrance to sec. C may be traced as follows; from B to contact 3l on track relay 29, to Wire 32, to Contact 33 on track relay 9, to wire 34, t0 H relay, to O. When this circuit is complete only the front contacts controlled by this H relay are closed and when this circuit is not complete only the back contacts controlled by this H relay will be closed. The circuit for the D relay for the signal at the entrance to sec. C may be traced as follows; from B to contact 44 controlled by the H relay of the signal in advance (that is, located at the entrance to sec. D), towire 45, to contact 46 on H relay for the signal at the entrance to sec. C, to wire 4l to D relay, to O. When this circuit is complete only the front contacts controlled by this D relay will be closed and when this circuit is not complete only the back contacts controlled by this D relay will be closed. The circuit for R lamp may be traced as follows; from B to contact 48 on H relay, to wire 49, to R lamp, to O. Only when this circuit is complete will R lamp be lighted. The .circuit for the Y lamp may be traced as follows; from B to contact 5l), to wire 5I, to contact 52 on D relay, to wire 53to contact 54 on I-I relay, to wire 55, to Y lamp, to O.. Only when this circuit is complete will Y lamp he lighted.` The circuit for G lamp may be` traced as follows; from B to contact 56, to Wire 5I, to contact 52. on D relay,.to wire 56, to G' lamp, to O. Only when this circuit is` completed will G lampbe lighted.

Still referring to Fig. 4; the normal. clearing circuit for train stop I I may be traced as follows; from B to contact i8 on I-I relay, to wire` 33, to mechanism I3, to O. The normal retaining circuit for train stop II maybe traced as follows; from B to contact I6 on track relay I0, to wire all, to wire I1, to contact 3.1 on track relay-,to wire 38, to contact 39 on operating mechanism i3, closed only when train stop I I is inthe non-stopping position, to wire 3D, to operating. mechanism I 3, to O.

My invention as incorporated in Fig. 4 includes the control of mechanism I3 by the auxiliary means including time delay means device 25. The control circuit of device 26 may be traced.. as follows: from B to contact I6 closed only` when sec.

B is occupied by a train, to wire aI1, to wire I1, to

wire bi1, to contact I4= closed only when train stop I2 is in the stopping position, to wire Ila., to contact i3 closed only when sec. C is occupied by a train, to wire I9, to device 26", to O. The circuit for the control ,of mechanism.- I 3 via device 26 is the same asdescribed hereinbefore in connection with Fig. 3, andis as follows: from B to contact 21 closed only afterthe lapse of the established time interval after the control `circuit for device 26 has been completed, to wire 28, to Wire 30, to mechanism I3, to O.

The functioning of device 26is the same as explained, hereinbeforain connection with Figs. 2 and 3, and it is believedlunnecessary to repeat it here.

The incorporation of my invention in an automatic block signal controlled train stop system, as in Fig. 4, is to provide a` means to. operate train stop II to the non-stoppingposition so that a train may pass, at restricted speed,.an automatic block signal which is displaying fa stop (R) signal or other restrictive signal indication.

As explained, hereinbefore, in connection with Fig, 1, distance Y is determined solely by the condition that contact` I 4 on train stop I2 closed only in the stopping position of train stop I2, is included in the control circuit of time delay means device 26. When the approach block (sec. B) is shorter than the longest train operated on the railroad contact I4 is located on a train stop farther in the rear.

The circuit for the H relay for the signal located at the entrance to sec. B may be traced asfollows; from B to contact 4U on track relay 9, to wire I1, to contact 4I on track relay I0, to wire 42, to H relay, to O. It will be observed that the circuit for the H relay for the signal located at the entrance to sec. B, in part, serves also for the normal retaining circuit for train stop operating mechanism I3 for train stop II.

The block signal system portrayed in Fig. 4 in general is old and well understood in the art and is illustrated only to show the incorporation of my invention in a block signal system.

Checking Contact 35 on device 26` is now included in the D relay control circuit for the signal located at the entrance to sec..B and this circuit may be traced as follows; from B to contact 51 on Hrelay for the signal at the entrance to sec. C, to wire 58, to contact 35 on device 26, to wire 59, to contact 66 on H relay for the signal at the entrance to sec. B, to wire 6I, to D relay, to 0.

The functioning of the visual lamp indication 25 is the same as explained in connection with Figs. l, 2, and 3, and it is believed unnecessary to repeat it here. Lamp 22 and control circuit of Figs. l, 2, and 3 is notincludedin Fig. lbecause the R lamp of the block signal serves the same purpose. A

Distances X andY are determined entirely on the same basis as has' been explained hereinbefore in connection with Fig. 1 and it is` believed unnecessary toirepeat it here. i

Secs;` A, B, C, D, andE and so on are similarly equipped.y

As shown in Fig. 4, secs. A, B, C, D, and-E are unoccupied, the train stops II and I2 are in the non-stopping position, and at all block signals the G lamps are lighted to inform aA train operator that the train may proceed. In proceeding over the track in thedirection of the arrow the train enters sec. B-and continues on to enter secs. C, D, and E. When the front end of the train enters sec. C, block signal lamp G at the entrance end-0f sec. G is extinguished andR lamp is lighted'and trainstop III is"y held in the non-stopping position by thenormal retaining-circuit. When the rear endof said-train passes out of sec. B, train stop II-assumes the stopping positionand remains in said stopping positionuntil the rear end of said train passesv out of sec. D (at which time the normalclearing circuit for mechanism I3 is reestablishe'd and at the signal atthe" entrance to sec. C the Y lamp indication is'displayed instead ofthe R lamp) unlesssaid train stop be put in the non-stopping position by a following train in a manner nowltobe described. Assume that the first train stopped with itsrear end occupying sec. D. Train stop- II is in thestopping position because the normal clearing circuit is open at contact 48 and the normal retaining circuit is open at-contacts I6; 31, and 39. A following train enters sec. B and continues on to enter sec. C. At the time said following trainentersu sec. B, contact I6 on relay Icloses andat the time said following train enters sec. C, contact I8 on relay 9. closes and thus the circuit for the control of time delay device 26 from B, contact I6, wire dI1, wire I1, wire I1b, contact Ill closed with trainlstop I2 in the stopping position,- wire I1a, contact IB, wire I 9, to device 26, to O, is completed. After the lapse of the established time interval of device 26, contact 21 on device 26 closes to complete a circuit from B, to contact 21 (now closed), to wire 28, to wire 36, tomeohanism I3, to O, whereupon train stop I lis operated to the non-stopping position and said following train may pass. The purpose of time delay device 26 and controll oircuittherefor and the control of train stop II by said device 26 is to` provide a means whereby train stop II may be operated tothe non-stoppingposition independently of the normal clearing circuit. In View of the fact that `theestablished time interval for device 26 does not star-t until aftercontact I8 closes (due to said following train entering sec. C) and that contact.-21 does not close, to complete the circuit tovmechanism I3, until at the end of said time interval, it is evident that said train stop I I will remain in the stopping position until after the established time interval after said following train enters sec. C (closing. of,4 contact I8). The control of mechanism I3 by time delay device 26, therefore, provides means'vvhereby the speed of a moving train is restricted to a predetermined speed While passing over distance X, While the R lamp indication is displayed at the signal at the entrance to sec. C, at which time the normal clearing circuit for train stop Ii is not complete. It is manifest that the brakes of said following train Will be applied by train stop l l in the event that the established time interval for device 26 has not elapsed before said train reaches said train stop H.

Attention is here directed to the fact that device 26 may be adjusted to require any desired time interval.

It is to be understood further that the scope of my invention contemplates contact i4 being included in the normal retaining circuit if desired.

It is to be understood further that the scope of my invention contemplates contact I4 being omitted entirely, if desired.

The object of train stop il is to enforce obedience to a restrictive signal and this is accomplished in my invention, hereinbefore disclosed, by providing an auxiliary control means including a time delay means for operating a train stop to the non-stopping position independently of the normal operating means and thus requiring a train to pass over any distance X immediately adjacent to the signal at a predetermined speed When said signal is displaying a restrictive signal, it being understood that back contact i6 on relay l may be omitted from the control circuit of time delay means device 26,

if desired, Without affecting, in any way, the restriction of train movement to any predetermined speed While passing over said any distance X.

I have shown the block signal at the entrance to each section as being located at the beginning of the track section and thereby retained the advantage of the block signal system functioning When the front end of a train is at the signal and the advance territory becomes unoccupied, and this feature requires only that the train stop of existing train stop and signal systems be relocated When incorporating my invention, but it is to be understood that the scope of my invention includes the location of the block signal in any desired location.

I desire it to be understood that applications of my invention as above described but modified to provide electrical control and pneumatic operation of the train stop operating mechanism are Wholly within the purview of this application.

The above rather specific description of forms of my invention is given solely by way of illustration, and is not intended, in any manner Whatsoever, in av limiting sense. Obviously my invention can assume many. different physical forms, and is susceptible of numerous modifications, and all such forms and modications are intended to be included, in this application, as coming Within the scope of the appended claims.

Having described my invention, what I claim is:

1. In an automatic train control and associated block signal system, a wayside train stop having a tendency to assume its stopping position, a mechanism for operating said train stop from its stopping position to its non-stopping position, a circuit and a source of energy for operating said mechanism, said automatic block signal system controlled by a front contact on a track circuit relay, said block signal system at times controlling said mechanism to operate said train stop from.

its stopping position to its non-stopping position, and auxiliary means for controlling said mechanism to operate said train stop from its stopping position to its non-stopping position, said auxiliary means including time delay means controlled by a back contact on said track relay, said auxiliary means at times controlling said mechanism to operate said train stop from its stopping position to its non-stopping position to permit the movement of a train moving at less than any predetermined speed over any predetermined distance in the approach to said train stop.

2. The invention set forth in claim 1, with said auxiliary means controlled by a back contact on an adjacent track circuit relay in series, said train stop assuming the stopping position after said adjacent track circuit becomes unoccupied by said train.

3. In an automatic train control system including a train stop having a tendency to assume its stopping position located at the Wayside and adapted When in the stopping position to co-act with train-carried apparatus to cause application of the train brakes, a mechanism for operating said train stop from its stopping position to its non-stopping position, a circuit including a source of energy for operating said mechanism, electrically controlled time delay means, a circuit and a source of energy for controlling said time delay means, said time delay means at times controlling said mechanism operating circuit, a first track circuit located Wholly in the approach to said train stop, a second track circuit located in part in the approach to said train stop and in part in advance of said train stop, said time delay means control circuit including a back contact controlled by said first track circuit and a back contact controlled by said second track circuit in series, said time delay means functioning to increase the time in which said mechanism Will operate said train stop from its stopping position to its non-stopping position after said train enters said second track circuit.

4. In an automatic train control system including a train stop having a tendency to assume its stopping position located at the Wayside and adapted when in the stopping position to co-act with train carried apparatus to cause application of the train brakes, a mechanism for operating said train stop from the stopping position to the non-stopping position, a circuit including a source of energy for operating said mechanism, a time delay device, a circuit including a source of energy for controlling said device, a first track circuit located wholly in the approach to said train stop, a second track circuit located in part in the approach to said train stop and in part in advance of said train stop, said time delay device controlling circuit including a back contact controlled by said first track circuit and a back contact controlled by said second track circuit in series, said device controlling said mechanism operating circuit. Y

5. The invention set forth in claim 4 with said time delay device controlling circuit also including in series a contact closed only in the stopping position of a train stop located in the approach to the train stop of claim 4,

6. The invention set forth in claim 4 With a visual indication system controlled by the train stop mechanism to inform the train operator as to whether said train stop is in the stopping position or inthe non-stopping position,

7 In an automatic train control and associated block signal system, a wayside train stop having a tendency to assume its stopping position, a mechanism for operating said train stop from its stopping position to its non-stopping position, a circuit and a source of energy for operating said 5 mechanism, said automatic block signal system controlled by a front contact on a track circuit relay for controlling said mechanism to operate said train stop from its stopping position to its nonstopping position, and auxiliary means for conlO trolling said mechanism to operate said train stop from its stopping position to its non-stopping position, said auxiliary means including time delay means controlled by a back contact on said track circuit relay, said auxiliary means at times l5 controlling said mechanism to operate said train stop from its stopping position to its non-stopping position when the associated block signal is displaying a restrictive speed signal indication.

8. The invention set forth in claim 7, with said 20 auxiliary means for operating said train stop from its stopping position to its non-stopping position when the associated block signal is displaying a stop signal indication.

9. The invention set forth in claim 7, with 25 said auxiliary means also controlled by a back contact on an adjacent track circuit relay in series with the back Contact specified in claim 7.

10. In an automatic block signal and automatic train control system including an automatic block 30 signal and train stop located at the wayside, said signal adapted to convey information to the operator of a train, said train stop having a tendency to assume its stopping position and adapted when in its stopping position to co-act with train carried apparatus to cause application of the train brakes, a signal mechanism for operating said signal, a train stop mechanism for operating said train stop from its stopping position to its non-stopping position, a source of energy, a circuit for controlling said signal mechanism, a normal clearing circuit including a contact on said signal mechanism to operate said train stop from its stopping position to its non-stopping position, a normal retaining circuit including a contact on said train stop closed only in the non-stopping position of said train stop for retaining said train stop in the non-stoppingposition, said signal mechanism control circuit including a front Contact on a track circuit relay, and auxiliary means for controlling said train stop mechanism to operate said train stop from its stopping position to its non-stopping position independently of said normal clearing circuit, said auxiliary means including a time delay means controlled by a back contact on said track circuit relay, said auxiliary means at times controlling said mechanism to operate said train stop from its stopping position to its non-stopping position to avoid causing application of the train brakes on a train moving at less than a predetermined speed in the adjacent approach to said train stop location.

11. The invention set forth in claim 10, with said auxiliary means for operating said train stop from its stopping position to its non-stopping position to avoid causing application of the train brakes on a train which stops at said train stop location.

GILBERT C. WHITNEY. 

